I cover science and public policy, environmental sustainability, media ideology, NGO advocacy and corporate responsibility. I'm executive director of the Genetic Literacy Project (www.GeneticLiteracyProject.org), an independent NGO, and Senior Fellow at the World Food Center's Institute for Food and Agricultural Literacy at the University of California-Davis. I've edited/authored seven books on genetics, chemicals, risk assessment and sustainability, and my favorite, on why I never graduated from college football player (place kicker) to pro athlete: "Taboo: Why Black Athletes Dominate Sports and Why We're Afraid to Talk About It". Previously, I was a producer and executive for 20 yeas at ABC News and NBC News. Motto: Follow the facts, not the ideology. Play hard. Love dogs.

Are GM foods harmful or nutritionally less beneficial when compared to conventional or organic foods? Scientists and regulators almost universally say “no.” That’s why a study published this week claiming that GM corn causes cancer in rats is creating such a furor. What’s the story behind the story? Jon Entine, executive director of the Genetic Literacy Project, reports.

Does Monsanto’s Roundup Ready corn (Europeans call it maize) cause health problems? It’s a reasonable question. It’s been asked and answered, at least to the satisfaction of most researchers.

There have been more than 100 peer-reviewed studies over the years—many by independent, non-industry scientists—that have demonstrated the safety of GM crops and food. This study by a team of French researchers in the journal Food and Chemical Toxicology is the first to seriously challenge the scientific consensus—and its release comes just in time to play a disruptive role in the upcoming California vote on Proposition 37, which would require mandatory labeling of all food products that include any biotech component.

In a nutshell, the team of French researchers claimed to have found that rats fed a high dose lifetime diet of Monsanto’s genetically modified corn or exposed to its top-selling weed killer Roundup suffered tumors and multiple organ damage.

Lead researcher Gilles-Eric Seralini of the University of Caen said they found that rats fed a diet containing NK603—a seed variety made tolerant to the spraying of Roundup—died earlier than those on a standard diet. They reported that 50 percent of males and 70 percent of females died prematurely, compared with only 30 percent and 20 percent in the control group.

Considering these controversial findings—out of synch with all of the published research so far showing GM food and crops to be safe and nutritionally equivalent or even superior (as a result of vitamin enhancement) to conventional and organic foods—it’s no surprise that the story exploded on the web. More than 10,000 articles appeared in a matter of hours.

It was euphorically received by anti-GM campaigners around the world who immediately moved to leverage the conclusions. “Setting aside possible health issues, the pervasive use of herbicide-resistant crops in the US is perpetuating a rapidly escalating arms race with insects and weeds that develop a resistance to the industry’s potent poisons as they become more common,” wroteAviva Shen at Think Progress. The study may also buoy anti-Monsanto food activists who organized 65 protests this past week alone at Monsanto facilities across the country.

The reaction to the report by scientists who are expert in this area has ranged from bewilderment to derision to hints of research malpractice.

“Even though I strongly support labeling, I’m skeptical of this study,” said Marion Nestle, professor in the Department of Nutrition, Food Studies and Public Health at New York University. “It’s weirdly complicated and unclear on key issues: what the controls were fed, relative rates of tumors, why no dose relationship, what the mechanism might be. I can’t think of a biological reason why GMO corn should do this.”

Mark Tester, a research professor for the Australian Centre for Plant Functional Genomics at the University of Adelaide noted that the findings raised the question of why no previous studies have flagged similar concerns. “If the effects are as big as purported, and if the work really is relevant to humans, why aren’t the North Americans dropping like flies? GM has been in the food chain for over a decade over there—and longevity continues to increase inexorably,” he wrote in a comment emailed to Reuters.

As one researcher noted, for nearly 20 years, billions of animals in the European Union and the United States have been fed soy products produced from genetically modified soybean, mainly from Latin America. Yet, no problems have been reported by the hundreds of thousands of farmers, officials and vets.

The London-based Science Media Centre, which assists reporters when major science news breaks, posted an entire page of criticisms from scientists, researchers and professors. David Spiegelhalter of the University of Cambridge writes that the methods, statistics and reporting of results were all below standard. Among the concerns highlighted:

The published does not present all the data. “All data cannot be shown in one report and the most relevant are described here’”—this is a quote from the paper, which means that no reader can evaluate the findings, which mean the data may have been cherry picked

Small sample size. The control group is inadequate to make any deduction. Only 10 rodents some of these develop tumors. Until you know the degree of variation in 90 or 180 (divided into groups of ten) control rodents these results are of no value.

Maize was minimum 11% of the diet—that’s nor a normal diet for rats and invariably distorted the data

In Fig. 2, the bars with a zero appears to be for the non-maize control, yet those bars don’t look significantly different from the bars indicating 11, 22, and 33% of GM maize in the diet. The authors do not appear to have done analysis of their data.

The data from the control group fed non-GM maize is not included in the main figures making it very difficult to interpret the results

No results given for non-gm maize

The same journal published a paper showing no adverse health effects in rats of consuming gm maize (though this is a shorter 90-day study)

Wendy Harwood, senior scientist at the John Innes Centre in Norwich, UK, reviewed the study, concluding: “The findings do not contradict previous findings that genetic modification itself is a neutral technology, with no inherent health or environmental risks. These results cannot be interpreted as showing that GM technology itself is dangerous.”

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Mr Entine, when you say that GMOs have been around for thousands of years you show a complete ignorance of genetic engineering.

Genetic engineering involves taking genes from one species and inserting them into another. For example, genes from an arctic flounder which has “antifreeze” properties may be spliced into a tomato to prevent frost damage.

Genetic engineering is in no way precise. It is impossible to guide the insertion of the new gene. This can lead to unpredictable effects. Also, genes do not work in isolation but in highly complex relationships which are not understood. Any change to the DNA at any point will affect it throughout its length in ways scientists cannot predict. The claim by some that they can is both arrogant and untrue.

GM bears no resemblance to traditional breeding techniques. The government’s own Genetic Modification (Contained Use) Regulations admit this when it defines GM as “the altering of the genetic material in that organism in a way that does not occur naturally by mating or natural recombination or both”.

Traditional breeding techniques operate within established natural boundaries which allow reproduction to take place only between closely related forms. Thus tomatoes can cross-pollinate with other tomatoes but not soya beans; cows can mate only with cows and not sheep. These genes in their natural groupings have been finely tuned to work harmoniously together by millions of years of evolution. Genetic engineering crosses genes between unrelated species which would never cross-breed in nature.

Substantial equivalence is a legal concept invented by the biotech industry. The industry claims that a GM food or food supplement is “substantially equivalent” to, or the same as, the non-GM version and therefore does not require labels or extensive testing.

Regulators have blindly accepted the substantial equivalence doctrine without backing up their belief with independent scientific research.

Jon, you seem to be as as hyper-pro-GMO as some of the people you complain about are against it. Just because we haven’t yet found a substantial direct cause of GMO foods leading to ill health does not mean that we should charge forth without concerns and consume them without any cautions. And what are these numerous health measures which you suggest in the statement above “Almost every health measure that we have in the US is trending downward. I’m just stunned at this ignorance.” What FACTS are you citing here, because I think the readers of Forbes would be interested in this statistic. Is Obesity trending downward? Diabetes? Alzheimiers? Celiac disease? ADD and ADHD? Depression? Anxiety? Irritable Bowl Syndromes? There may not be any direct evidence as to the cause being GMO, but do you really believe that there is not a food or nutritional epidemic going on right in front of us? Is it not true that the American diet as it is exported internationally is also causing a rise in these problems in new markets outside the U.S.?

I am pro science–period. No, there is no evidence of a food or nutritional epidemic. There is zero evidence–none based on empirical evidence–that any food with a GMO as part of it has resulted in any unusual health issues. When you move proteins, there is always a chance that any specific individual might be allergic to that specific protein (just as there are some people who are allergic to almost any substance in the world) but there is zero evidence that any health issue is related to the process of genetic modification. All foods should be monitored for potential allergens. Foods made through biotechnology are no different and should be treated in the way we treat all foods. That’s science. Anything else is not science.

Sadly most people are either too stupid or lazy to be able to implement an objective and empirical view. People are somewhat right (in some ways, think checks and balances) to view big gov’ts and corporations with a critical eye but in this case as in many others, this attitude is holding back society a bit. Or should I say could, if this mania over GMOs increases, hold back society. It’s just too bad that people are so responsive to fear tactics. I’m sure whole foods and the like are providing generous funding to these groups, and with great returns (I hear sales of non-GMO labeled foods have gone up 30%) but they are small and “organic” and those are two words people have applied a very positive connotation to in regard to food products. I am personally much more worried about pesticides and the adaptations pests have made to them.

Jon, You stated: “the result of genetic modification over thousands of years”, “there is nothing biologically unusual about adding a protein to a crop. Humans have done that for thousands of years.”

Are you implying or trying to make the claim that the genetic modification of a transgenic organism, involving the mutation, deletion or insertion, from completely different species, is the biological equivalent of a hybrid organism, and/or the biological equivalent of same species breeding?

I just find it interesting how “experts” throughout history have debunked public concerns about things that threaten health, yet years later are found to be harmful and banned; lead in Paint and DDT to name a couple. You’d think the absence of independent and controlled studies on genetic modification would be a red flag, in and of itself. Shouldn’t controlled studies be a requirement BEFORE the such are introduced to the public? It would seem those same scientists debunking a study that showed possible harm to the public health should be vocal in demanding that better or more studies be conducted to ensure our health. I don’t understand their mindset.

I’d be happy to respond to substantive comments. What exactly did you find so reprehensible? That 90% of scientists do not believe that GM crops or foods pose any safety or health concerns? That’s just a fact. That even anti-GM activists find this study disgraceful. You can just peruse the web to confirm that. That journalist such as myself are widely reporting that this study appears brazenly political? Articles from The Atlantic to Reuters are making the same claims. It’s important to stick to empirical data and not be ruled by politics or emotions, particularly on issues of such importance. Again, if you have some factual concerns rather than just a tirade, I’ll be responsive.

I hope the French government also notes that they were able to grow GMO corn and conventional corn on adjacent plots without contamination. I am constantly told that’s not possible, but it’s right there in their methods section.